1. Technical Field
The present invention relates to a drive circuit for a switching element which is a target to be driven (hereinafter, referred to as “target switching element”). The target switching element is a voltage control type switching element. The drive circuit includes an integrated circuit. The target switching element opens and closes a current path by electronically controlling an absolute value of a potential difference between a reference end which is one end of the current path and an opening and closing control terminal.
2. Related Art
For example, JP-A-2012-16110 discloses a configuration in which IGBTs (Insulated gate bipolar transistors) configuring an inverter for an in-vehicle traction unit are used as target switching elements, and a drive circuit driving the target switching elements includes an integrated circuit. According to this technique, a controller generating operation signals for the IGBTs outputs the operation signals to the integrated circuit via a photocoupler.
Meanwhile, incorporating a photocoupler and the like into an integrated circuit can manufacture the whole control system in smaller size compared with externally attaching the photocoupler and the like to the integrated circuit. If an insulation communication means such as a photocoupler is incorporated into an integrated circuit, it is required that a high-voltage side area, which is connected to a gate of an IGBT in the integrated circuit, and a low-voltage side area, into which operation signals are inputted, are insulated from each other in the integrated circuit. In this case, the number of terminals required to be connected to the high-voltage side area tends to be larger than the number of terminals required to be connected to the low-voltage side area. Hence, disadvantages are found when the insulation communication means is incorporated into an integrated circuit. For example, the integrated circuit is redundantly designed.